If the knee of the pressure gauge were connected to the atmosphere, the mercury level in the knees would be the same. The level difference is 76 mm. Consequently, the gas pressure is 76 mm higher than the atmospheric pressure and is equal to 825,002098 mm Hg.
749 Torr is equal to 749.002098 millimeters of mercury
825.002098 millimeters of mercury is equal to 109 990.926 pascals